Mounting tungsten filaments.



c. P. SCOTT. MOUNTING TUNGSTEN FILAMENTS.

APPLICATION FILED DEC. 12, 1908.

1,013,227. Patented Jan.2,191 2 3 SHEETS-SHEET l llllm INVENTOI? 7 M 7K??? 0. F. soon. MOUNTING TUNGSTEN PILAMENTS. APPLICATION FILED DBO. 22. 1908';

, 3 SHEETS-SHEET 2.

4 41mm rs Patented Jan. 2; 1912.

c. I. soon". 7 MOUNTING TUNGSTEN FILAMENTS; I

APPLICATION FILED BBQ-'22, 1908.

Y Patented Jan. 2,1912.

8 sums-41mm 3.

.. the filament midway citizen of the United States,

Allegheny, State of cable to fragile filaments through loops or at the ends firmly cinemas 1*. score,

01 PITTSBURGH, PENNSYLVANIA, ASSIG-NOR TO WESTINGHOUSE LAMP COMPANY, A CORPORATION OF.PENNSYLVANIA MOUNTING ruues'rnu rrnamnu'rs.

Specification of Letters Patent.

' Patented-Jan. 2,1912.

Application filed December 22, 1908. Serial'No. 468,706.

To all whom it may concern: I

Be it known that I, CHARLES F. Soon, a and resident of Pittsburgh, county of Pennsylvania, have invented certain new and useful Improvements in Mounting Tungsten Filaments, of which the following is a specification.

My invention relates to a method of and means for supporting filaments for incandescent electric lamps and is particularly applisuch, for instance, as those made of tungsten, tantalum, molybdenum, etc.,. although many "features of my invention are applicable to filaments of other material. Heretofore'it' has been customary to rigidly cement or fuse the endsof the filaments into metallic leading-in or supporting wires and to provide anchors for the loops of' the filaments. In the case of tungsten filaments, flexible or yielding supports have been used for the supporting wires as well as for the anchors, and various other means have been proposed for guarding against sudden jars and stresses being placed upon the filaments and which are liable to break them.

My invention contemplates mounting the filaments loosely in their supports instead of rigidly fastening them to their supports. The current carrying contact is therefore a mechanical contact, the surfaces usually being held in contact by tension upon the filament.

In its simplest form a straight filament may have its two ends bent into hooks which are hooked over terminals through which current passes.' Filaments of other shapes, such as of hair pin shape, may have the two ends bent into hooks which pass loosely hooks in the leading-in or in this case the bend of between itsends will preferably be supported by a suitable anchor wire which exerts a tension upon the filament thereby holding the hooked connections in place. In ordinary practice it is customary/co rigidly fasten the end of the filamentto its supporting wire.

supporting wires;

The connection is sometimes made by a ce it renders a filament find it advantageous ment or-paste and sometimes by fusing a metal supporting wire around the end of the filament. In the manufacture of tungsten lamps, for example, a method in common practice is to surround the end of the filament by a small hook at the end of a supporting wire. This hook is then subjected to an electric spark or are which melts the supporting wire causing it to form in a globule, or ball around the tungsten filament. This method of fastening the filaments is objectionable for several reasons. It is a delicate operation and. cannot be conducted in the air, but, inorder to prevent oxidation of the filament, must be conducted in a new tral gas; the arc is liable to heat and damage the filament. Moreover when the lamp is completed the filament is held rigidlyat one end, which in the case, for example, of a tungsten filament, is quite unsatisfactory, as which, is inherently fragile all the more likely to be broken, as a blow or shock brings a maximum stress at -the point of rigid support. It is well known that filaments in commercial lamps are most likely to break near the point of rigid support.

In order to remove these difliculties in the manufacture of the rigidly supported. filament, and to avoid these characteristics in the completed lamp, I have devised a method of mechanical connection. This construction is comparatively sim le, and the filament, as it is not rigidly held, is permitted a degree of freedom which obviates the liability to breakage by shock which is found in the rigidly supported filament. v

In carrying out my invention, various forms of construction may be applied.

A filament, whether it takes the form of a straight wire or of a hair pin, may have its two ends bent backward in the form of' a hook, and this hook may pass over the supporting wire or through a hook, bend, or loop in the supporting wire, or the hook in the filament may pass through a loose link, which is, in turn, mechanically held by the supporting wire. In some cases I to form a helical coil in the leading-in or supporting wire or in v the loose link and pass the bent end of the opportunity for the hook to straighten out .filament attaches of such form when heated. In other cases I find it advan tageous to form en eye in the end of the filament by taking, the end of'the hook and bending it around the filament, so as to prevent the hook from straightening out. When this-construction is used it is desirable to have the support or link to which the that it may readily pass through the eye in the end of the filament. This form reduces the tomperature at theepoint of contact between the filament and its support as it offers two paths for the current to flow. The current in passing fi'om the support divides an'd flows through the two sides of the eye at filament, uniting agaln at the point of contact between the 'end and the straight part of the filament;

en several filaments are to be su ported in a single lamp and connected m series, the several filaments maybe hooked to common supports at the pomts where they are to be electrically connected in series, so' that current may pass fromsone to the other. If the construction of the lamp be'such that no external support is required at the junction of two filaments,

they may be hooked together directly.

The method of mechanically attaching filaments to their. supports lends itself to mounted upon an arbor.

forms of constructlon which would be difficult tocarry out with the use of a fused contact. Several forms of special construction are shown in the fi es.

In the drawings; Figure 1 illustrates a filament, for tance, made from tlmgsten and adapted to be ut' ed according to my invention. Fig. 2 shows two such filaments Figs. 3, 4 5, 6, 7,

g 8, 9, 10, 11 and 11, illustrate varlous difwhich in turn carries two I helical coils 7,7, at their ends.

"tioual supporting wire,

modifications. 1 represents a .filahaving its ends bent hooks'may be formed ferent adaptations and- Referring to Fig. 1, ment of hairpin shape mto hooks 2, 2. These by first sufliciently heating the metal, for instance, as tungsten,

or if madeof other material the hooks may be formed thereon when the-filament is made.

In Fig. 21 have shown a stem, 3, of an incandescent lamp carrying an arbor, 4, supporting books or anchors, 5, 5. The supportinganohors 5, 5, may be made of nickel or other suitable materiaL- -The stem 3 carries lead' -in wires, 6, 6, which after passing through the stem extend outward laterally and have An addi 8, is also shown, it

3 having no electrical connection. It also carries at its opposite end a similar coil 9.

The hooks 20 the filaments are passed upwardlv through the several spirals, two of upon the ends of the them being-passed through the same spiral 9 upon the "supporting wire 8. The helical coils obviate any tendency which might otherwise exist on the part of thehooks to straighten out and releasethemselves from the leading-in or supporting wires. The loopsof the filaments pass through hooks or rings 10, which, in case the filaments are of tungsten, of tungsten cross-section The hooks and usually of somewhat larger than that-10f, the filaments. or 10 are carried by hooks anchors 5. The anchor wlres may be made small and exert a slight tension upon the filaments. Th structure when thus repared is inserted into the lamp bulb in t e usual manner,

Fig. 3, a completed'lam is shown contaimng four filaments. in w 'ch the loops' filaments pass through 10 and the hooked ends also extend through rings, 11, of tlmgsten or other suitable material. The'rings, 11, are in turn,carried by the books, 12, upon the ends of the leading-in and supporting wires. Inasmuch as there might be avtendency, however, for the hooks as shown in" Fig. .3, to straighten out, it is sometimes preferable, although not always essential to adopt the structure shown in Fig. 4, in which the rings are replaced by hooks or rings having helical coils 8, for receiving the hooks of the filament.

are with advantage also made tungsten rings In Fig. 5 I have shown a slightly different form of hook at the looped end of the filament from that shown .in Fig. 3.

he loops or rings are usually of larger cross-section than the filaments themselves and as they do not convey the current they do not become suificiently heated to straighten out. The ,looped ends of the filaments are there shown as being spread apart considerably beyond the dimensions of the opening through w passed into the base of the lamp. In order to place the mounted filaments of this structure the bulb, th which support the looped ends of the filaments are moved over their supporting spring wires to a point near the centra glass arbor. The sprmg'wires are then bent upward parallel with .the arbor and the whole structure is put into the bulb. By working through the smallvhole at the to; end of the lamp prior to its being exhauste the spring supporting wires are bent into their proper positions and the hooks or rings which carry the looped ends of the filaments are passed out to the ends of the supporting wires and are held in hooks at the ends of-these wires. 7

In Fig. 6, a modification lsshown 1n which an open eye or loop is formed ateach end of the filament to receive the supporting wire. This eye is formed by twlstmg e rings or hooks the filament about itself so as to prevent it from opening under the influence of heat.

In- Fig. 7, a form is shown inwhich two filaments are spread apart in a manner similar to that shown in Fig. 5*, the hooked ends of the filaments bein held in loose rings which may be'of nicke or other suitable material. In this instance the spread of the filaments is such as to afford a good end on light.

In Fig.8, a somewhat similar construction is shown except that the filaments are not spread apart as in Fig. ,7, and the filaments are mounted in practically the same manner as shown in Fig. 2.

Fig. 9 shows a lamp with a single filament in which the ends are hooked into helical coils formed in the co per leading-in wires. The ends of these leading-in wires project a suflicient distance beyond the coils to afford additional paths for conducting away and radiating the heat. The loopedend of the filament is held in a tungsten or other suitable h'ook, this being supported by a suitable wire which may be of nickel or other suitable material. This construct-ion is found to be peculiarly adapted for large amperage.

In Fig. 10, a modification is shown in which two filaments are mounted independently, the hooked ends of the filaments passing through independent helical coils, the

filaments being connected in series through.

a V-shaped wire having coils at each. end instead of having the hooks of two filaments pass through a single coil.

In Fig. 11, a construction is shown in which the hooked ends of the filaments are supported upon wires spreading the ends of the filaments-apart a greater distance than the opening through which they are inserted.

into the globe. This is accomplished in essentially the same manner as described with reference to the looped filaments in connection with Fig. 5. v p

Heretofore it has generally been customary to mount the filaments of tungsten lamps practically parallel with the central arbor, such construction being convenient and more or less necessary when the filaments are rigidly fused to their supports,

The general flexibility afl'orded by the mebe understood that instead of employing any one of a-variety chanical connection, in accordance with my inventiom-facilitates the varied forms which are shown in the several figures and which are typical of the results that may be secured by this method of construction. It will also hairpin shaped filaments, filaments which are straight and have hooks upon each end can be mounted in various forms, securing of positions within the globe. It is also practicable with this construction'to insert filaments of either the hairpin shape or straight form into the globe metal other than tungsten,

thus rethrough the small hole at the top, fil

pairing lamps in which one or more ments may have become broken.

In practice I find that a mechanical contact of the ends of the filaments with the leading-in and supporting wires in many cases affords a sufliciently connection, particularly when a slight stress is exerted upon them by a suitable spring.

By employing tungsten'frings and hooks for making direct contact with the tungsten filaments, the hot current carrying tungsten filament does not come into contact with thereby avoiding liability of overheating metals of relatively lower melting point. The tungsten ring or hook may, if desired, be directly fused to the leading-in or supporting wire.

In Fig. 11, a modification is shown in whichthe wire is made V-shape so that while affording a loose connection it nevertheless tends togrip the filament slightly, thus holding the filament in contact with the supporting wire. In this construction the end of the filament has a species of pivotal contact connection permitting considerable freedom of-movement incertain directions while a good electrical contact is -form of construction is useful where the lamp is liable to be subjected to considerable shock or vibration.

I claim as my invention;

The method of constructing incandescent electric lamps, which consists in mounting the filaments loosely upon their supporting wires, placing the filaments parallel with the supporting arbor, bending the supports together, inserting the structure within the globe, and'thereafter bending outward the supporting wires and spreading the filaments.

good electrical insured. This 2'. In an incandescent electric lamp, a filaj ment having hooked ends, supporting wlres for the filament, and helical coils carried by the supporting wires and engaging the hooked ends of the filament.

3. An incandescent lamp comprising a filamenthaving hooked ends, supporting wires for the filament, and helical coils loosely carried by the supporting wires and engaging the hooked ends of the filament.

4. Anlncandescent lamp comprising a filament, supporting wires therefor, and helica1 coils loosely carried by the supporting wires and loosely surrounding but engaging the ends of the filament.

5.. An incandescent lamp comprising a pluralityof reversely bent filaments, the legs of different filaments crossing but not engaging each other.

6. An incandescent lamp comprising a plurality of reversely bent filaments, the legs of difierent filaments crossing but not engaging each other, and the legs ofcertain of them being those of others.

spread farther apart than 7. An incandescent lamp comprising a zig-zag filament, certain of the-straight por- 5 'tions of which cross 'but do not engage each other.

Signed at New York, in the'co unty of New York and State 0 10th day of December A;

Witnesses WM. H. CAPEI),

f New York D. 190.8.

- An riimz S. KNIGHT.

, this v 

